Many of today's manufacture or assembly processes are almost completely automated, requiring human intervention only for programming which processes to run. Many of these processes require a system to convey work pieces from one station to another. At each station, operations, such as adding components, may be performed on the work pieces.
Conveyor systems take many forms. Belt systems have existed for a long time. More recently, systems have been developed in which work pieces are placed on top of one or more rollers, some of which are drive rollers and others of which are idler rollers. Frictional forces between the work pieces and the drive rollers propel the work pieces along the conveyor system. Sufficient frictional forces, which depend on the weight of the work pieces being conveyed, must be maintained, or the work piece will slip. The likelihood of a work piece slipping is increased as the drive roller accelerates at higher rates and rotates at higher velocities. Higher acceleration rates and velocities are desirable in production because they reduce per-unit manufacturing time.
Many processes, such as the automated production of relatively small electronic or electromechanical devices, require precise work piece positioning. Often, this precise work piece positioning involves conveying the work piece to a more general location, lifting the work piece from the conveyor system, and precisely orienting the work piece so that an operation may be performed on the work piece. This three-step process consumes valuable time. When the consumed time is multiplied by hundreds or thousands of work pieces, the resultant loss in productivity may be substantial.
As the work piece is lifted from the conveyor system and oriented, components may be dislodged from the work pieces. Dislodged components may cause substantial quality assurance problems and may result in diminished productivity. The lift-and-orient operation may also result in damage to the work pieces due to impact shock.